1. Field of the Invention
The instant invention relates to apparatus for optimizing power factor in electrical installations, and in particular to a KVAR sizing unit and method of use for determining the capacitance to connect to a given load in order to optimize power factor.
2. Background of the Invention
The loads served by electric utility companies are generally primarily resistive (such as incandescent light bulbs) or primarily inductive (such as induction motors). The inductive loads draw a combination of kilowatts (real power) and kilovars (reactive power). Capacitors are a static source of kilovars.
Capacitors installed at inductive loads provide a number of benefits: reduced electrical energy consumption, reduced line current, increased voltage at the load, better voltage regulation and lower losses. These benefits are accomplished by installing sufficient capacitor kilovars (KVAR) at the load to bring power factor to just under unity. Power factor is equal to real power (kilowatts) divided by reactive power (kilovars).
Additional benefits associated with the optimization of power factor at an inductive load include increased equipment life due to lower operating temperature, protection against electrical surges such as those caused by lightning, and increased capacity at the electrical panel.
Inductive equipment that would benefit from power factor optimization include air conditioners, heat pumps, refrigeration equipment, irrigation pumps, pool pumps, etc. In small residential installations, the power factor of the entire house may be optimized at the house's circuit breaker panel. In large residential, commercial and industrial settings the power factor of individual components may be optimized at the component's location at the load side of the component's switching device. Examples of this larger type of inductive equipment include air conditioners, refrigeration equipment and chillers, amonia systems used in refrigeration systems, commercial washers and dryers, irrigation pumps (in the agricultural area), conveyers, etc.
Unfortunately, capacitors are not used to optimize load factor as widely as they might be. One reason for this has been the lack of a simple apparatus and method to optimize load factor. Utility company engineers have the technical background to size capacitors to correct load factor for electric utility companies, but in general, no such capability exists in the residential, commercial, industrial and agricultural areas. As a result, more electrical energy than is necessary is used to power inductive loads.